OOP Classes / Windows - C / C++ / MFC Discussion Boards

Re: Overloading and virtual functions

CPallini31-Jan-08 9:24

CPallini

31-Jan-08 9:24

BTW, the following is allowed

int _tmain(int argc, TCHAR* argv[], TCHAR* envp[])
{
  CBaseClass *pCDerivedClass = new CDerivedClass();
  pCDerivedClass->DoSomething(5,5);
}

Please note: error check and cleanup left to the reader...

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

[my articles]

Re: Overloading and virtual functions

bob1697231-Jan-08 9:59

bob16972

31-Jan-08 9:59

Noted.

I had become complacent with being able to call any function implemented in the base class regardless of whether it was virtual using a pointer from any level in the derived hierarchy when there were no overloaded functions in the base class. This kinda throws me curve ball but I'm learning.

Thanks for the info.

Re: Overloading and virtual functions

Mark Salsbery31-Jan-08 9:31

Mark Salsbery

31-Jan-08 9:31

hmm...what happened to inheritance?

CDerivedClass is a CBaseClass.

Logically, this doesn't seem like it should be an error.
Until you convince me otherwise Smile | :)

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: Overloading and virtual functions

led mike31-Jan-08 8:36

led mike

31-Jan-08 8:36

bob16972 wrote:
Thanks for the advice on how to cope with it. You don't by any chance know what is responsible, topic wise, for this behavior?

Is this because of the concept of "Hiding"? I'm not sure what topic I need to google for to better understand it.

Polymorphism[^]

Therefore, what the virtual keyword does is to allow a member of a derived class with the same name as one in the base class to be appropriately called from a pointer, and more precisely when the type of the pointer is a pointer to the base class but is pointing to an object of the derived class

led mike

Re: Overloading and virtual functions

bob1697231-Jan-08 9:15

bob16972

31-Jan-08 9:15

thanks. I guess the part that is confusing me is why a pointer, at any level, will invoke the base implementations when no function is overloaded (and not implemented in a derived class) but a pointer at the base class is required when functions are overloaded and an implementation for at least one overloaded function is not provided in the derived class.

Re: Overloading and virtual functions

Brian R19-Mar-08 9:14

Brian R

19-Mar-08 9:14

You can add a using statement to promote the visibility of the base class functions.

class CDerivedClass : public CBaseClass
{
public:
CDerivedClass(void) {}
using CBaseClass::DoSomething;
virtual ~CDerivedClass(void) {}
virtual void DoSomething(int a) {}
};

The eliminates the "hiding" problem.

Re: Overloading and virtual functions

bob1697212-Apr-08 19:57

bob16972

12-Apr-08 19:57

That seems to fix the issue. Smile | :)

Thanks for the help. Now I need to go back and undo the workaround code and the half baked solution I put in.

OOP Classes / Windows

egerving31-Jan-08 6:20

egerving

31-Jan-08 6:20

? I understand the basics of OOP and classes. But all the general info always talks about the box, the cat, the dog, the car etc. No one ever talks about user interface, database etc. Can someone shed some light on these subjects? Seems to me that for a compete program one would have to develop various class modules so to speak.
Thanks.

Re: OOP Classes / Windows

David Crow31-Jan-08 7:12

David Crow

31-Jan-08 7:12

egerving wrote:
No one ever talks about user interface, database etc. Can someone shed some light on these subjects?

You might want to look at MFC. It has several classes for UI components (e.g, CListBox, CEdit) and databases (e.g., CDatabase). While those are specific examples, it shows that most anything can be thought of an as object.

"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Re: OOP Classes / Windows

Maximilien31-Jan-08 8:16

Maximilien

31-Jan-08 8:16

A cat is a box with four legs.
A car is a box with four wheels.

Maximilien Lincourt
Your Head A Splode - Strong Bad

Re: OOP Classes / Windows

Mark Salsbery31-Jan-08 8:29

Mark Salsbery

31-Jan-08 8:29

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: OOP Classes / Windows

CPallini31-Jan-08 8:59

CPallini

31-Jan-08 8:59

That is because OOP primary objective was zoo simulation.
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

[my articles]

Re: OOP Classes / Windows

Maximilien31-Jan-08 9:02

Maximilien

31-Jan-08 9:02

zoop ?

Maximilien Lincourt
Your Head A Splode - Strong Bad

Re: OOP Classes / Windows

CPallini31-Jan-08 9:05

CPallini

31-Jan-08 9:05

ZOOP for the sake of precision!
Big Grin | :-D

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

[my articles]

Re: OOP Classes / Windows

Maximilien31-Jan-08 9:09

Maximilien

31-Jan-08 9:09

w00t! z00p!!

Maximilien Lincourt
Your Head A Splode - Strong Bad

Running a new ActiveX Control help.

TheBerk31-Jan-08 5:48

TheBerk

31-Jan-08 5:48

Hi, this is my first time ever using ActiveX (so please bare with me) and I'm having trouble getting a control to work. I'm trying to use the control ScintillaVB (it can be found here http://www.ceditmx.com/scivb/index.asp[^] ) on a VC++ 2005 project (I'm also running Vistax64, maybe that's a factor), but when I place the .ocx on the form and run it, nothing shows up on the new window. I've followed all the directions given on the site, but maybe I don't understand using ActiveX controls well enough. Could someone please take a look at this, or give me a little help on the steps for setting up a ActiveX control in VC++ 2005 ? Thank you!

Re: Running a new ActiveX Control help.

Mr. Surprise31-Jan-08 7:23

Mr. Surprise

31-Jan-08 7:23

If you have an already Registered ActiveX Control, you may use to the "Microsoft Visual C++ ActiveX Test Container" i suggest to you as by secondary step.

Thread problem

Orell31-Jan-08 5:03

Orell

31-Jan-08 5:03

1......

UINT lesson(LPVOID prog)
{
CMainDlg *dlg=(CMainDlg*)AfxGetApp()->GetMainWnd();
Sdlg->UpdateData();

CString l_mesg=mesg;
int l_index=l_mesg.Find('@');
CString l_name=l_mesg.Left(l_index);
CString l_id=l_mesg.Right(l_mesg.GetLength()-l_index-1);

int L_ITEMS = dlg->m_lessonlistcontrol.GetItemCount();
int l_pos=dlg->m_lessonlistcontrol.InsertItem(L_ITEMS,l_name,0);
dlg->m_lessonlistcontrol.SetItemText(l_pos,1,l_id);

dlg->UpdateData(0);
AfxEndThread(0,true);
return 0;
}

void CMainDlg::Receive()
{

stusock.Receive(mesg,rsize);
AfxBeginThread(lesson,NULL,THREAD_PRIORITY_NORMAL,0,0,NULL);
}
///////////////////////////////////////////////////////////
2..............

UINT lesson(LPVOID prog)
{
CMStudentDlg *Sdlg=(CMStudentDlg*)AfxGetApp()->GetMainWnd();
Sdlg->UpdateData();

CString l_mesg=mesg;
int l_index=l_mesg.Find('@');
CString l_name=l_mesg.Left(l_index);
CString l_id=l_mesg.Right(l_mesg.GetLength()-l_index-1);

int L_ITEMS = Sdlg->m_lessonlistcontrol.GetItemCount();
int l_pos=Sdlg->m_lessonlistcontrol.InsertItem(L_ITEMS,l_name,0);
Sdlg->m_lessonlistcontrol.SetItemText(l_pos,1,l_id);

Sdlg->UpdateData(0);
AfxEndThread(0,true);
return 0;
}

void CMStudentDlg::Receive()
{

stusock.Receive(mesg,rsize);
AfxBeginThread(lesson,NULL,THREAD_PRIORITY_NORMAL,0,0,NULL);
}

/////////////////////////
pls tell where am wrong the main diffrence is the 1st one is in the main dialog of the application of the project which i am doing in VC6 its working with out any problem

but the sencond one its is not written in the main dialog but in a newly inserted dialog its'nt showing any error when i run the project but its not showing the reqired result ie no values is displayed or some time its show run time error

Re: Thread problem

led mike31-Jan-08 5:07

led mike

31-Jan-08 5:07

JOBYTHOMAS24 wrote:
pls tell where am wrong

Please provide a link to the documentation you read that told you to use AfxEndThread(...) in the way you are using it.

led mike

Re: Thread problem

Orell31-Jan-08 5:16

Orell

31-Jan-08 5:16

void AFXAPI AfxEndThread(UINT nExitCode, BOOL bDelete = TRUE); in afxwin.h

this is what am getting when right click on AfxEndThread and goes for its definition

Re: Thread problem [modified]

led mike31-Jan-08 5:38

led mike

31-Jan-08 5:38

JOBYTHOMAS24 wrote:
void AFXAPI AfxEndThread(UINT nExitCode, BOOL bDelete = TRUE); in afxwin.h

So you think the declaration in the header file is the documentation? No it is not.

Check this out[^]

And follow the linked content that says:

For more information on AfxEndThread, see the article Multithreading: Terminating Threads.

If you want to be a software developer you are going to have to read more than header files. Wink | ;)

Last modified: 3hrs 42mins after originally posted -- fixed URL in link

led mike

Re: Thread problem

CPallini31-Jan-08 8:56

CPallini

31-Jan-08 8:56

Hey Mike, I wasn't able to find the quoted sentence. Anyway I've learned a lot of valuable information about XSL transformations, thanks.
Big Grin | :-D

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

[my articles]

Re: Thread problem

led mike31-Jan-08 9:21

led mike

31-Jan-08 9:21

Wow, I guess I picked a bad day to stop smoking crack!

Should be fixed now

led mike

Crack pusher STILL needed!

CPallini31-Jan-08 9:27

CPallini

31-Jan-08 9:27

Too generous: two links!
Laugh | :laugh:

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

[my articles]

Re: Thread problem

CPallini31-Jan-08 5:22

CPallini

31-Jan-08 5:22

If CMStudentDlg isn't the main dialog, why are you casting a pointer to the main dialog to (CMStudentDlg *)?

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

[my articles]

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